A chain saw, as a gardening electrical power tool, is extensively used in household, gardening, and like fields. A working principle of the chain saw is that a powering device drives a transmission mechanism which in turn drives the saw chain to cut. During operation, a large amount of heat is generated due to friction between the saw chain and other elements; therefore lubrication needs to be performed timely to prevent damage to the saw chain due to quick rises in temperature. Hence, an oil supply system is generally disposed in a housing of the chain saw and includes an oil tank for storing the lubricant and an oil pump connected with the oil tank. The oil tank delivers the lubricant to the oil pump via an oil pipe, and the oil pump is adjacent to the chain and supplies the lubricant to the saw chain to lubricate the chain.
The above oil supply system has the oil pump as a kernel assembly. Oil leakage of the oil pump body is a crucial factor affecting stability of the oil supply system of the chain saw product. The oil supply systems of many chain saws available in the market will be confronted with oil leakage during use and storage of the machine, thereby causing problems such as undesirable lubrication effect of the machine, waste of resources and environmental pollution.
In addition, after a user fills the lubricant to the full and uses the chain saw for a period of time, the chain saw usually is placed for a period of time and then continues to be used. During placement of the machine, the lubricant is often stored in an oil can. If it is not properly sealed, the lubrication often leaks out of the machine, which causes waste of resources and environmental pollution and affects hygienic conditions upon use of the machine. In current chain saw products, a bolt is used to tightly press an oil outlet pipe to interrupt an oil circuit. Generally, there are two methods for adjusting the bolt. One is to adjust the bolt via an external tool. As this method requires use of other tools this method causes much inconvenience. The other is to adjust the bolt via used of an adjusting accessory without using other external tools, for example, to adjust the bolt by use of a regulating knob at a top end of the bolt. However, both of the above two methods require the user to perform additional steps associated with specifically operating the bolt so the chain saw is not conveniently or quickly usable. On the other hand, if the user forgets to press the bolt tightly, oil leakage will occur.